Reactivity of pyridinium poly(hydrogen fluoride) towards silicon tetrachloride, trichlorosilane and tris(amino)silanes

Abstract

The reaction of silicon tetrachloride (SiCl 4), trichlorosilane (HSiCl 3) and tris(amino)silanes[(R 2N) 3SiH] with pyridinium poly(hydrogen fluoride) (PPHF) gives rise to hexafluorosilicatesalts in good yields. They have been characterized as pyridinium hexafluorosilicate(C 5H 5NH) 2SiF 6 (in the case of SiCl 4 and HSiCl 3) and the corresponding dialkyl ammoniumhexafluorosilicate (R 2NH 2) 2SiF 6 salts [for tris(amino)silanes] (where R 2N=pyrrolidino,piperidino, hexamethyleneimino, morpholino, N-methylpiperazino and diethylamino). Theinteresting features of these reactions are the cleavage of SiCl, SiH and SiN bondsat room temperature by PPHF and fluorination of the silicon moiety to a hexa-coordinateddoubly charged anionic species. These compounds have been characterized by NMR ( 1H, 29Si, 19F) and IR spectroscopy, and by chemical analysis.